1). Field of the Invention
This invention relates to a reflow furnace for an electronic assembly and to a method of assembling an electronic assembly.
2). Discussion of Related Art
An electronic assembly such as a motherboard or a card of a computer typically includes a printed circuit board to which one or more devices such as semiconductor packages including processors, memory etc. are mounted. A device is located on the printed circuit board and solder paste is applied to the printed circuit board and a conductive wire, or the like, of the device. The electronic assembly is then heated to cause reflow of the solder. The electronic assembly is then allowed to cool which causes solidification of the solder. The solder thereby provides a mechanical and electrical connection between the device and the printed circuit board.
The printed circuit board may have metallic contacts on one or more edges thereof. When the electronic assembly is heated, the solder starts migrating to the metallic contacts. The solder tends to travel across a surface of the printed circuit board. The printed circuit board may also have hollow vias therein. Tiny solder balls may be located within the vias which blow out of the vias when the electronic assembly is heated. Solder migrating to the metallic contacts can attach to the metallic contacts and so render the electronic assembly defective.